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On a stepper motor driver we have the high voltage section where we connect the required power and we also have the signal section where the wiring from the stepper motors connect.
I use shielded cables for both the high voltage and signal sections and my question is do I ground the shielded cable in both sections or just the high voltage or signal section?
Right now only the shielded cable ground wire from the high voltage section goes to my star point ground.
Thanks
Any Ac Power Grounds are separate from Shield Grounding, and should never share the same connection pointsQuote:
Originally Posted by kolias
For the shields to have any use at all they need to be clamped to the Ground Plane at Both Ends, Signal shielded wires in some cases can be Grounded (Clamped) at the source end, if you were to have any interference problems
A P-Clip is one of the best ways to clamp a Shield to the Ground Plane, this needs to be a tight clamp when fastened
Here are some snips of how it should be done
Thank you mastec54,
I’m not aware what is “Ground Plane”, can you please explain?
Reading about Ground Plane it’s get more confusing. So in my cnc control panel (about 20”x20”x 9”) I have the 4 stepper drivers, 3 PSU’s and a BOB along with ESS. If I get a piece of metal 3”3”x1/8” thick would that be considered a Ground Plane? If not, any suggestions?
Here is two definitive papers on grounding and bonding by Siemens.Quote:
Originally Posted by kolias
I have used these methods over the years with no kind of problems experienced.
See the one on shield grounding that has changed when carrying out equi-potential bonding of the earth conductors.
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Thank you Al for the information
What is everything mounted on, this is normally a Metal Panel and unpainted wherever anything is mounted this must be paint freeQuote:
Originally Posted by kolias
The Ground Bus is attached to the Ground Plane, (Ground Bus is where all Grounds connect Star Ground) so in your cabinet the Ground Plane is the metal panel that everything is mounted on
Outside the Cabinet the machine is the Ground Plane, the machine and the Cabinet are Grounded Bonded together from the Ground Bus to the Machine
So, the Ground Plane can be any part of the machine or cabinet if correctly wired
If not done this way nothing would be safe to use
"Ground Plane" does not refer to a single physical entity, it is the electrical continuity of all the metallic parts of the machine that are at the same earth GND potential.Quote:
Originally Posted by kolias
Now it is all clear, many thanks to both
Yes. All shields terminated at one end only, your star point. If second end not connected no current can flow in the shield and induce currents in enclosed wires.Quote:
Originally Posted by kolias
That used to be the original criteria for shielded cables, read Ch6 of the Siemens Motion Control I posted.Quote:
Originally Posted by neilw20
With the original introduction of low voltage control systems, ground bonding of the machine was not carried out, consequentially it was found that grounding both ends of a shield caused ground loops to occur. imposing current in the shield.
The problem is that although eliminating ground loops, the shield grounded at one end makes for a good antenna !!
Now it is recommended that with equi-potential bonding, this eliminates any variation of ground voltages in the system, therefore allowing the ground bonding of both ends of the shield, as per the Siemens recommendation.
No That is incorrect Shields need to terminate at Both Ends, in most cases, or they are become ineffective, these sips pretty much sums it up as to how Shields need to be TerminatedQuote:
Originally Posted by neilw20
You must never terminate a shield direct to a Ground Bus (Star Ground Point)